Apparatus and method for channel coding and multiplexing in CDMA communication system

ABSTRACT

A channel coding and multiplexing apparatus and method in a CDMA communication system is disclosed. In the channel coding and multiplexing apparatus, each of a number of radio frame matchers (equal in number or greater than the number of transport channels) has a radio frame segmenter and segments each of transport channel frames that may have different transmission time intervals to radio frames. A multiplexer multiplexes the radio frames to form a serial data frame.

PRIORITY

This application is a continuation of application Ser. No. 09/603,062,filed Jun. 26, 2000, now U.S. Pat. No. 7,386,001, and claims priority totwo applications entitled “Apparatus and Method for Channel Coding andMultiplexing in CDMA Communication System” filed in the KoreanIndustrial Property Office on Jun. 25, 1999 and assigned Serial No.1999-26221 and “Apparatus and Method for Channel Coding and Multiplexingin Channel in CDMA Communication System” filed in the Korean IndustrialProperty Office on Jul. 7, 1999 and assigned Serial No. 1999-27163, thecontents of both of which are hereby incorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates generally to a channel communicationapparatus and method in a mobile communication system, and inparticular, to a channel coding and multiplexing apparatus and method inwhich multi-transport channel frames are converted to multi-physicalchannel frames.

2. Description of the Related Art

A conventional CDMA (Code Division Multiple Access) mobile communicationsystem primarily provides a voice service. However, the future CDMAmobile communication system will support the IMT-2000 standard, whichcan provide a high-speed data service as well as the voice service. Morespecifically, the IMT-2000 standard can provide a high-quality voiceservice, a moving picture service, an Internet browsing service, etc.This future CDMA communication system will be comprised of a downlinkfor transmitting data from a base station to a mobile station and anuplink for transmitting data from the mobile station to the basestation.

It will thus be desirable for the future CDMA communication system toprovide various communication services such as simultaneous voice anddata communications. However, details are yet to be specified for thesimultaneous implementation of voice and data communications.

SUMMARY OF THE INVENTION

It is, therefore, an object of the present invention to provide achannel coding and multiplexing apparatus and method in which atransport channel frame data is segmented into plurality of radio framesin a transmitting device of a CDMA communication system.

It is also an object of the present invention to provide a channelcoding and multiplexing apparatus and method in which each of the dataframes of a plurality of transport channels is segmented into radioframes and the segmented radio frames are multiplexed to form a serialdata frame at every radio frame transmission time interval (TTI) in atransmitting device of a CDMA communication system.

It is another object of the present invention to provide a channelcoding and multiplexing apparatus and method in which each of the dataframes of a plurality of transport channels is segmented into radioframes, the segmented radio frames are multiplexed to form a serial dataframe at every radio frame TTI, and the serial data frame is segmentedinto a plurality of physical channel frames to transmit the physicalchannel frames on a plurality of physical channels in a transmittingdevice of a CDMA communication system.

It is a further object of the present invention to provide a channelcoding and multiplexing apparatus and method in which a transportchannel frame data is added with filler bits and segmented into radioframes in a channel transmitting device of a CDMA communication system.

It is still another object of the present invention to provide a channelcoding and multiplexing apparatus and method in which received physicalradio frames are demultiplexed to form plurality of radio frames and theradio frames are desegmented to form a transport channel frame in achannel receiving device of a CDMA communication system.

It is yet another object of the present invention to provide a channelcoding and multiplexing apparatus and method in which data framesreceived via multi-code physical channels are desegmented to form aserial data frame and demultiplexed to form radio frames of eachtransport channels in a receiving device of a CDMA communication system.

To achieve the above objects, a channel coding and multiplexingapparatus and method in a CDMA communication system has as many radioframe matchers as transport channels and a multiplexer. Each radio framematcher has a radio frame segmenter and segments a transport channelframe that may have a different transmission time interval from thetransmission time intervals of other transport channel frames in othertransport channels to form radio frames and the multiplexer multiplexesthe radio frames to a serial data frame.

BRIEF DESCRIPTION OF THE DRAWINGS

The above and other objects, features and advantages of the presentinvention will become more apparent from the following detaileddescription when taken in conjunction with the accompanying drawings inwhich:

FIG. 1 is a block diagram of an embodiment of an uplink channeltransmitting device according to the present invention;

FIG. 2 is a block diagram of an embodiment of a downlink channeltransmitting device according to the present invention;

FIG. 3 is a view illustrating the operation of the channel transmittingdevices shown in FIGS. 1 and 2;

FIG. 4 is a block diagram of an embodiment of a channel receiving deviceaccording to the present invention;

FIG. 5 is a flowchart illustrating a radio frame generation procedureusing filler bits according to the present invention;

FIG. 6 is a flowchart illustrating a radio frame generation procedurewithout using filler bits according to the present invention;

FIG. 7 is a flowchart illustrating an embodiment of a radio framemultiplexing procedure according to the present invention; and

FIG. 8 is a flowchart illustrating an embodiment of a physical channelframe generation procedure according to the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Preferred embodiments of the present invention will be describedhereinbelow with reference to the accompanying drawings. In thefollowing description, well-known functions or constructions are notdescribed in detail since they would obscure the invention inunnecessary detail.

The present invention defines in detail radio frame segmentation,multiplexing, and physical channel segmentation for channel coding &multiplexing in a channel communication device of a CDMA communicationsystem. That is, radio frame segmentation, multiplexing of radio frames,and segmentation of the multiplexed radio frames into physical channelframes, that are not provided by the 3GPP Technical Specification forMultiplexing and Channel Coding, TS 25.212 version 1.0.0 1999. 05. 05,will be defined fully enough to deal with bit-basis operations. The 3GPPTechnical Specification for Multiplexing Channel Coding, TS 25.212version 1.0.0 1999. 05. 05, published by 3GPP Organizational Partners ishereby incorporated by reference.

Prior to description of the present invention, terms as used herein willbe defined. “Transport channel frame” or “input data frame”: a dataframe applied to the input of a radio frame matcher from a channelcoder; “Radio frame”: a data frame formed by segmenting the inputtransport channel frame, where the size of the radio frame is a functionof the transmission time interval (TTI) of the input transport channelframe and the radio frame TTI as explained below. A transport channelframe may be transmitted at a different data rate for a different TTI.

The following description is conducted with the appreciation thatparticular details like a radio frame TTI and the insertion position ofa filler bit are given by way of example for comprehensive understandingof the present invention. Therefore, it is clear to those skilled in theart that the present invention can be readily implemented without thedetails or by their modifications.

A description will now be made of the structures and operations of 3GPPuplink and downlink channel coding and multiplexing apparatusesincluding first interleavers through second interleavers according to anembodiment of the present invention.

FIGS. 1 and 2 are block diagrams of uplink and downlink channeltransmitting devices, respectively, according to an embodiment of thepresent invention. Receiving devices for receiving information from thechannel transmitting devices have the reverse configurations of theircounterparts. FIG. 3 is a view referred to for describing the operationsof the channel transmitting devices shown in FIGS. 1 and 2.

In accordance with the embodiment of the present invention, data framesreceived via at least two transport channels may have different TTIs anddifferent data rates. Radio frame matchers 101, 102, . . . 10N (i.e.,“101 to 10N”) receive the data frames of the corresponding transportchannels, segment the received data frames into data of a size, which isa function of the transport channel frame TTI and the radio frame TTIs(i.e., radio frames), and sequentially output the segmented radio frames(The “N” is used throughout in the reference number notation to indicatean indefinite number of respective components). Each of the radio framematchers 101 to 10N includes an interleaver for compensating for fading,a radio frame segmenter for segmenting an interleaved transport channelframe into radio frames, and a rate matcher for controlling the datarate of the radio frames by puncturing/repeating certain parts of theradio frames. In the case where the bit number of a transport channelframe is not a multiple of a radio frame length, a corresponding radioframe matcher inserts a filler bit into the transport channel frame,which is performed in its radio frame segmenter by way of example in theembodiment of the present invention.

A multiplexer 200 sequentially multiplexes radio frames sequentiallyreceived from the radio frame matchers 101 to 10N to a serial datastream.

In case of the multicode transmission, a physical channel segmenter 300segments the serial data stream received from the multiplexer 200 intodata frames as many as the number of physical channels using at leasttwo codes and transfers the data frames to the corresponding physicalchannels, so that the serial data frame can be transmitted on thephysical channels.

In case of a single code transmission, the physical channel segmenter300 does not need to segment the serial data stream, but insteadtransmits the serial data stream on a physical channel.

Referring to FIGS. 1 and 3, reference numeral 100 denotes the entireblock of channel coding & multiplexing chains having the radio framematchers 101 to 10N for receiving N encoded data that may have differentqualities of service (QoS) in parallel. In other words, data streamsapplied to the radio frame matchers 101 to 10N from MAC (Medium AccessControl) and higher layers (transport block/transport block set) mayhave different QoS. Specifically, transport channel frames may havedifferent data rates and different TTIs and each radio frame matcherreceives frame data from a corresponding channel coder. The same coderoutputs frame data of the same QoS during each service. However, duringanother service, the QoS of the same coder may change to another QoS.Therefore, data of different QoS may be applied to the radio framematchers 101 to 10N, but each radio frame matcher receives frame data ofthe same QoS during each individual service.

Each radio frame matcher receives encoded frame data having a differentdata frame size and a frame transmission period according to its QoSfrom a corresponding channel coder. QoS is determined by voice, data,and images. Accordingly, the data rate and TTI of frame data depend onits QoS. In the embodiment of the present invention, it is assumed thatdata frames have TTIs of 10, 20, 40, or 80 msec. According to itsservice type, input coded data may have a different data rate and adifferent TTI. In other words, frames of each channel have a unique TTIand data rate. In the case where data of one channel is to betransmitted, encoded data generated from one channel coder is processedand in the case where data of two channels is to be transmitted, encodeddata generated from two corresponding channel coders are processed.

Each of first interleavers 111 to 11N primarily interleaves a transportchannel frame received from a corresponding channel coder. Here, achannel frame received from each channel coder may have a different TTIand a different data rate.

As shown in FIG. 1, radio frames are referred as RF and are indexed asfollows: RF_(i,j) where i=transport channel index and j=radio frameindex for a given transport channel and RF_(i) refers to all of theradio frames in the i^(th) transport channel (e.g., RF_(1,2) means asecond radio frame in a first transport channel and RF₁ refers to all ofthe radio frames in the first transport channel). Radio frame segmenters121 to 12N segment data frames LF₁ to LF_(N) received from the firstinterleavers 111 to 11N, respectively, into radio frames RF₁ to RF_(N),respectively, as indicated by reference numeral 301 in FIG. 3 and inFIG. 1, and output the radio frames RF₁ to RF_(N) sequentially in theorder of segmentation. In embodiments of the present invention, T_(i)refers to the number of radio frames in a transport channel i wherei=transport channel index (e.g., T₁ is equal to the number of radioframes in the first transport channel).

Here, the transport channel frames LF₁ to LF_(N) may have different TTIsand different data rates according to their channels. The radio frameTTI is assumed to be 10 ms in the embodiment of the present invention.Thus, each of the radio frames RF₁ to RF_(N) contains as much data as 10ms duration frame of the input transport channel frame. In this case, aradio frame segmenter, if it receives a transport channel frame of a80-ms TTI, segments the 80-ms data frame into eight radio framessequentially, and sequentially outputs the radio frames. A radio framematcher, which receives a transport channel frame of a 40-ms TTI,segments the 40-ms data frame into four radio frames sequentially In thesame manner, a radio frame matcher, which receives a transport channelframe of a 20-ms TTI, segments the 20-ms data frame into two radioframes sequentially. A 10 ms-data frame is equal in duration to theradio frame TTI and thus output without segmentation.

A transport channel frame length in bits may not be an integer multipleof the radio frame length in bits. In this case, it is preferable toinsert a filler bit into the transport channel frame to make thetransport channel frame length in bits as long as a multiple of theradio frame length in bits. That is, if L_(i)/T_(i) (L_(i): the lengthof an input transport channel frame in the i^(th) transport channel andin certain embodiments of the present invention, T_(i)=TTI for i^(th)transport channel/10 msec) is not an integer, a filler bit is inserted.The filler bit is pre-processed prior to radio frame segmentation inorder to maintain a radio frame length constant for a transmissionperiod. Transmission of the whole transport channel frames is easilycontrolled by keeping a radio frame length constant within the TTI ofthe transport channel frames. When a transport channel frame has themaximum TTI of 80 msec, seven filler bits can be used at maximum. Thedecrease of transmission efficiency that arises from an increase in thewhole data frame rate caused by addition of these filler bits isnegligibly small. The radio frame segmenters 121 to 12N sequentiallysegment input transport channel frames into 10-msec radio frames RF₁ toRF_(N) as indicated by reference numeral 302 in FIG. 3. The ratematchers 131 to 13N adjust the data rates of the radio frames RF₁ toRF_(N) received from the radio frame segmenters 121 to 12N,respectively, and output data frames KF₁ to KF_(N), respectively K_(i)refers to the length of the respective KF_(i) frames.

The above radio frame matchers 101 to 10N receive correspondingtransport channel frames in parallel, check the sizes of the transportchannel frames, segment the transport channel frames into radio frames,and output the radio frames in parallel. The multiplexer 200 multiplexesthe data frames KF₁ to KF_(N) received from the rate matchers 131 to 13Nto a serial data stream of size P as indicated by reference numeral 303in FIG. 3. Here, the multiplexer 200 can sequentially multiplex the dataframes KF₁ to KF_(N). In this case, the size of the multiplexed frameP=K₁+K₂+ . . . +K_(N). Therefore, the multiplexer 200 first determinesthe number N of transport channels, receives radio frames in parallelfrom the radio frame matchers 101 to 10N, and sequentially multiplexesthe radio frames to a serial data frame. That is, the multiplexer 200outputs a serial data frame indicated by 303 in FIG. 3.

A physical channel segmenter 300 segments the multiplexed frame of sizeP received from the multiplexer 200 into M physical channel frames asindicated by 304 in FIG. 3 (M is the number of available physicalchannels) and feeds the physical channel frames to second interleavers401 to 40N. Here, each physical channel frame is as long as P/M. Thephysical channels may use multiple codes. Hence, the physical channelsegmenter 300 sets the number M of available physical channels, segmentsthe multiplexed serial data frame into M physical channel frames, andassigns them to the corresponding physical channels. The multiplexedserial data frame can be segmented into one or more physical channelradio frames of the same data rate. Alternatively, the multiplexedserial data frame can be segmented into one or more physical channelframes of different data rates.

An uplink channel receiving device for receiving radio frames from theuplink channel transmitting device shown in FIG. 1 performs theoperation of the uplink channel transmitting device in the reverseorder. The uplink channel receiving device will be described later withreference to FIG. 4.

The operation of each component shown in FIG. 1 is illustrated in FIG. 3in detail.

Referring to FIG. 3, reference numeral 301 denotes segmentation oftransport channel frames received in parallel from the firstinterleavers 111 to 11N into radio frames which will be transmitted fromthe radio frame segmenters 121 to 12N. If L_(i)/T_(i) is not an integer,a corresponding radio frame segmenter inserts a filler bit to make L_(i)be a multiple of T_(i). As shown in FIG. 3, filler bits are sequentiallyinserted into radio frames, preferably beginning with the last radioframe.

The reference numeral 301 in FIG. 3 illustrates the procedure for addingfiller bits to the radio frames. The procedure is explained in detail inthe subsequent sections. The embodiment of the present invention isdescribed in the context with the case that one filler bit 0 or 1 isinserted into one radio frame. Reference numeral 302 indicates ratematching of the radio frames according to their data rates. Referencenumeral 303 indicates multiplexing of N radio frames of size K_(i) (i=1,2, . . . , N) after rate matching to one multiplexed frame of size P andtransmission of the multiplexed frame to the physical channel segmenter300. Reference numeral 304 indicates segmentation of the multiplexedframe into M physical channel frames and parallel assignment of the Mphysical channel frames to physical channels.

FIG. 2 is a block diagram of a downlink channel transmitting device fordownlink channel coding & multiplexing, illustrating radio framematchers 151 to 15N through second interleavers 800.

The downlink channel transmitting device operates in the same manner asthe uplink channel transmitting device shown in FIGS. 1 and 3 exceptthat the outputs of radio frame segmenters 171 to 17N are applied to theinput of the multiplexer 600. Rate matchers are not shown in the drawingbecause they are disposed before the first interleavers in the downlinkchannel transmitting device of FIG. 2.

A downlink channel receiving device is the same in operation as theuplink channel receiving device except that it does not perform ratedematching.

A description will be given primarily of the radio frame segmenters,multiplexers, and physical channel segmenters in the channeltransmitting devices constituted as shown in FIGS. 1 and 2 according tothe embodiment of the present invention. For better understanding of thepresent invention, the description will be confined to the uplinkchannel transmitting device. Therefore, the radio frame segmenters arelabeled with 121 to 12N, the multiplexer with 200, and the physicalchannel segmenter with 300.

Radio Frame Segmentation Using Filler Bit

Uplink and downlink radio frame segmenters operate in the same manner.The radio frame segmenters 121 to 12N segment input transport channelframes into 10-msec radio frame blocks and sequentially output the radioframes. During this operation, filler bits may or may not be insertedinto a transport channel frame according to the bit number of thetransport channel frame. In the embodiment of the present invention,insertion of filler bits is implemented in the radio frame segmenters121 to 12N if filler bits are inserted. One filler bit is inserted intoone radio frame and filler bit insertion begins with the last radioframe. A description of inserting a filler bit into a transport channelframe and then segmenting the transport channel frame into radio framesin the radio frame segmenters 121 to 12N referring to FIG. 5 willprecede that of segmenting a transport channel frame into radio frameswithout inserting filler bits in the radio frame segmenters 121 to 12Nreferring to FIG. 6.

In case the ratio (L_(i)/T_(i)) of the size of a transport channel frameapplied to the input of a radio frame segmenter to the radio frame TTIis not an integer, the number r_(i) of filler bits is calculated in thefollowing way in order to make L_(i)/T_(i) an integer. Since T_(i)ranges from 0 to 8, r_(i) ranges from 0 to 7. (L_(i)+r_(i))/T_(i)achieved with the use of filler bits is defined as KD_(i) and R_(i),respectively for the downlink and the uplink.r _(i) =T _(i)−(L _(i) mod T _(i)), here r _(i)={0, 1, 2, 3, 4, 5, 6, 7}downlink: KD _(i)=(LD _(i) +rD _(i))/TD _(i)LD_(i), rD_(i) and TD_(i) are L_(i), r_(i) and T_(i) for the downlink,respectivelyuplink: R _(i)=(L _(i) +r _(i))/T _(i)

If the number r_(i) of filler bits is not 0, a filler bit is added tothe last bit position of each of corresponding radio frames from a(T_(i)−r_(i)+1)^(th) radio frame in order to maintain a frame lengthconstant, i.e., KD_(i) or R_(i). 0 or 1 is arbitrarily selected as afiller bit. The filler bit has little to do with performance and servesas a reserved bit that can be selected by a system user. It can becontemplated that the filler bit is designated as a discontinuoustransmission (DTX) bit so that a transmitter does not transmit thefiller bit after channel coding & multiplexing. The radio frame blocksthat are modified to have a constant radio frame length in the abovemanner are fed to the multiplexer 200. Then, the operation of the radioframe segmenters on a bit basis will be described in detail.

As for bits prior to radio frame segmentation in an i^(th) radio framematcher 10 i, it is assumed that the number r_(i) of filler bits hasalready been calculated and 1≦t≦T_(i) (t indicates a radio frame index).t=1 for the first radio frame, t=2 for the second radio frame, andt=T_(i) for the last radio frame. Each radio frame has the same size,(L_(i)+r_(i))/T_(i). Then, the output bits of a first interleaver 11I ofthe i^(th) radio frame matcher 10 i is taken to be b_(i,1), b_(i,2), . .. , b_(i,Li) and the output bits of the radio frame segmenter 12 i istaken to be c_(i,1), c_(i,2), . . . c_(i,[(Li+ri)/Ti]) in 10-msec frameunits for T_(i)=TTI (msec) of an i^(th) transport channel/10 (msec) ε{1, 2, 4, 8}. Then

-   output bits of the radio frame segmenter for the first 10 msec: t=1    c _(i,j) =b _(i,j) , j=1, 2, . . . , (L _(i) +r _(i))/T _(i)-   output bits of the radio frame segmenter for the second 10 msec: t=2    c _(i,j) =b _(i,(j+(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i))/T _(i)-   output bits of the radio frame segmenter for the (T_(i)−r_(i))^(th)    10 msec: t=(T_(i)−r_(i))    c _(i,j) =b _(i,(j+(Ti−ri−1)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i)    +r _(i))/T _(i)-   output bits of the radio frame segmenter for the    (T_(i)−r_(i)+1)^(th) 10 msec: t=(T_(i)−r_(i)+1)    c _(i,j) =b _(i,(j+(Ti−ri)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i)−1)/T _(i)    c _(i,j)=filler_bit(0/1), j=(L _(i) +r _(i))/T _(i)-   output bits of the radio frame segmenter for the T_(i) ^(th) 10    msec: t=T_(i)    c _(i,j) =b _(i,(j+(Ti−ri)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i)−1)/T _(i)    c _(i,j)=filler_bit(0/1), j=(L _(i) +r _(i))/T _(i)

The radio frame segmenter 12 i is included in a transmitting device andits counterpart is a radio frame desegmenter in a receiving device.Radio frame desegmentation is equivalent to the reverse operation ofradio frame segmentation in that 10-msec blocks received for atransmission period are sequentially arranged and assembled into oneframe.

FIG. 5 illustrates a radio frame generation process using filler bits inthe above-described manner. Variables as used below will first bedefined.

t: frame time index (1, 2, . . . , T_(i));

RF_(i,t): a t^(th) 10 msec radio frame in an i^(th) radio frame matcher;and

L_(i): input frame size from the i^(th) radio frame matcher.

Referring to FIG. 5, the radio frame segmenter performs aninitialization process in step 511:t:=1/*frame time index initialization*/r _(i) :=T _(i) −L _(i) mod T_(i)/*number of filler bits*/R _(i):=(L _(i) +r _(i))/T _(i) for UL (uplink)/*radio frame size foruplink*/KD _(i):=(LD _(i) +rD _(i))/TD _(i) for DL (downlink)/*radio frame sizefor downlink*/

In step 513, the radio frame segmenter checks whether the number r_(i)of filler bits is 0. If the number r_(i) of filler bits is 0, the radioframe segmenter reads data of a radio frame size from an input frame andstores it in step 517. On the other hand, if the number r_(i) of fillerbits is not 0, the radio frame segmenter checks whether a frame index tis (Ti−r_(i)+1) in step 515, that is, a current radio frame is to beadded with a filler bit. In the case of a radio frame that will not beadded with a filler bit, the radio frame segmenter reads data of a radioframe size from an input frame and stores it in step 519 and proceeds tostep 525. In the case of a radio frame that will be added with a fillerbit, the radio frame segmenter reads data one bit smaller than a radioframe size from the input frame and stores it in step 521. The radioframe segmenter inserts the last bit position of the stored radio framein step 523, increases the frame index t by 1 in step 525, and checkswhether the updated frame index t is larger than the segment numberT_(i) corresponding to the radio frame TTI in step 527. If the frameindex t is smaller than the segment number T_(i) corresponding to theradio frame TTI, the radio frame segmenter returns to step 513. If theframe index t is larger than the segment number T_(i) corresponding tothe radio frame TTI, the radio frame generation procedure ends. Radioframes generated in this manner are sequentially fed to the secondmultiplexer 200.

Radio Frame Segmentation Without Inserting Filler Bits

A radio frame segmenter that does not use filler bits may be usedinstead of the above described radio frame segmenter. Since T_(i) rangesfrom 0 to 8, r_(i) ranges from 0 to 7. (L_(i)+r_(i))/T_(i) for thedownlink and the uplink are defined as KD_(i) and R_(i), respectively.r _(i) =T _(i)−(L _(i) mod T _(i)), here r _(i)={(0, 1, 2, 3, 4, 5, 6,7}downlink: KD _(i)=(LD _(i) +rD _(i))/TD _(i)uplink: R _(i)=(L _(i) +r _(i))/T _(i)

The bit-basis operation of the radio frame segmenter that does not usefiller bits will be described in detail.

As for bits prior to radio frame segmentation in the i^(th) radio framematcher 10 i, it is assumed that the number r_(i) of filler bits hasalready been calculated and 1≦t≦T_(i) (t indicates a radio frame index).t=1 for the first radio frame, t=2 for the second radio frame, andt=T_(i) for the last radio frame.

Then, let the output bits of the first interleaver 11 i in the i^(th)radio frame matcher 10 i be b_(i,1), b_(i,2), . . . , b_(i,Li) and letthe output bits of the radio frame segmenter 12 i be c_(i,1), c_(i,2), .. . , c_(i,(Li+ri)/Ti) in a 10-msec frame unit for T_(i)=TTI (msec) ofthe i^(th) transport channel/10 (msec) ε {1, 2, 4, 8}. Then

-   output bits of the radio frame segmenter for the first 10 msec: t=1    c _(i,j) =b _(i,j) , j=1, 2, . . . , (L _(i) +r _(i))/T _(i)-   output bits of the radio frame segmenter for the second 10 msec: t=2    c _(i,j) =b _(i,(j+(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i))/T _(i)-   output bits of the radio frame segmenter for the (T_(i)−r_(i))^(th)    10 msec: t=(T_(i)−r_(i))    c _(i,j) =b _(i,(j+(Ti−ri−1)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i)    +r _(i))/T _(i)-   output bits of the radio frame segmenter for the    (T_(i)−r_(i)+1)^(th) 10 msec: t=(T_(i)−r_(i)+1)    c _(i,j) =b _(i,(j+(Ti−ri)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i))/T _(i)-   output bits of the radio frame segmenter for the T₁ ^(th) 10 msec:    t=T_(i)    c _(i,j) =b _(i,(j+(Ti−ri)(Li+ri)/Ti))) , j=1, 2, . . . , (L _(i) +r    _(i))/T _(i)

If r_(i) is not 0, the size of the first to (T_(i)−r_(i))^(th) radioframes is R_(i) and the size of the (T_(i)−r_(i)+1)^(th) to the lastradio frames is (R_(i)−1). For downlink, if rD_(i) is not 0, the size ofthe first to (TD_(i)−rD_(i))^(th) radio frames is KD_(i) and the size ofthe (TD_(i)−rD_(i)+1)^(th) to the last radio frames is (KD_(i)−1). Radioframe blocks of sizes varied with time are fed to the multiplexer. Dueto the variable radio frame size, a frame size in the multiplexer mayvary at every 10 msec intervals and the physical channel segmenter mayalso operate differently at every 10 msec intervals, making control offrame size complicated. Accordingly, it is preferable to employ a radioframe segmenter which inserts filler bits.

The radio frame segmenter 12 i is included in a transmitting device andits counterpart is a radio frame desegmenter in a receiving device.Radio frame desegmentation is equivalent to the reverse operation ofradio frame segmentation in that 10-msec blocks received for atransmission period are sequentially arranged and assembled into oneframe.

FIG. 6 illustrates a radio frame generation process without insertingfiller bits in the above-described manner. Variables as used hereinbelowwill first be defined.

t: frame time index (1, 2, . . . , T_(i));

RF_(i,t): a t^(th) 10 msec radio frame in an i^(th) channel coding &multiplexing chain; and

L_(i): input frame size from the i^(th) channel coding & multiplexingchain.

Referring to FIG. 6, the radio frame segmenter performs aninitialization process in step 611:t:=1/*frame time index initialization*/ri:=T _(i) −L mod T _(i)/*number of filler bits*/R _(i):=(L _(i) +r _(i))/T _(i) for UL (uplink)/*radio frame size foruplink*/KD _(i):=(LD _(i) +rD _(i))/TD _(i) for DL (downlink)/*radio frame sizefor downlink*/

In step 613, the radio frame segmenter checks whether the number ri offiller bits is 0. If the number r_(i) of filler bits is 0, the radioframe segmenter reads data of a radio frame size from an input frame andstores it in step 617. On the other hand, if the number ri of fillerbits is not 0, the radio frame segmenter checks whether a frame index tis (T_(i)−r_(i)+1) in step 615. If the frame index t is smaller than(T_(i)−r_(i)+1), the radio frame segmenter reads data of a radio framesize from an input frame and stores it in step 619 and proceeds to step623. If the frame index t is equal to or greater than (T_(i)−r_(i)+1),the radio frame segmenter reads data one bit smaller than a radio framesize from the input frame and stores it in step 621. The radio framesegmenter increases the frame index t by 1 in step 623, and checkswhether the updated frame index t is larger than the segment numberT_(i) corresponding to the radio frame TTI in step 625. If the frameindex t is smaller than the segment number T_(i) corresponding to theradio frame TTI, the radio frame segmenter returns to step 613. If theframe index t is greater than the segment number T_(i) corresponding tothe radio frame TTI, the radio frame generation procedure ends. Radioframes generated in this manner are sequentially fed to the multiplexer200.

Multiplexing

The multiplexer 200 for the uplink will be described. Bits as describedbelow are applied to the input of the multiplexer 200.

-   output bits of rate matcher #1: c_(1,1), c_(1,2), . . . , c_(1,K1)-   output bits of rate matcher #2: c_(2,1), c_(2,2), . . . , c_(2,K2)-   output bits of rate matcher #3: c_(3,1), c_(3,2), . . . , c_(3,K3)-   . . .-   output bits of rate matcher #N: c_(N,1), c_(N,2), . . . , c_(N,KN)

The output bits d₁, d₂, . . . , d_(p) of the multiplexer 200 arewhen j=1, 2, 3, . . . ,P(P=K ₁ +K ₂ + . . . +K _(N)),d _(j) =c _(i,j) j=1, 2, . . . , K ₁d _(j) =c _(2,(j−K1)) j=K ₁+1, K ₁+2, . . . , K ₁ +K ₂d _(j) =c _(3,(j−(K1+K2))) j=(K ₁ +K ₂)+1, (K ₁ +K ₂)+2, . . . , (K ₁ +K₂)+K ₃. . .d _(j) =c _(N,(j−(K1+K2+ . . . +KN−1))) j=(K ₁ +K ₂ + . . . +K_(N−1))+1, (K ₁ +K ₂ + . . . +K _(N−1))+2, . . . , (K ₁ +K ₂ + . . . +K_(N−1))+K _(N)

Then, the operation of the multiplexer 200 for the downlink will bedescribed below.

Bits as described below are applied to the input of the multiplexer 200.

-   output bits of rate matcher #1: c_(1,1), c_(1,2), . . . , c_(1,K1)-   output bits of rate matcher #2: c_(2,1), c_(2,2), . . . , c_(2,K2)-   output bits of rate matcher #3: c_(3,1), c_(3,2), . . . , c_(3,K3)-   . . .-   output bits of rate matcher #N: c_(N,1), c_(N,2), . . . , c_(N,KN)

The output bits d₁, d₂, . . . , d_(p) of the multiplexer 200 arewhen j=1, 2, 3, . . . ,P(P=K ₁ +K ₂ + . . . +K _(N)),d _(j) =c _(i,j) j=1, 2, . . . , K ₁d _(j) =c _(2,(j−K1)) j=K ₁+1, K ₁+2, . . . , K ₁ +K ₂d _(j) =c _(3,(j−(K1+K2))) j=(K ₁ +K ₂)+1, (K ₁ +K ₂)+2, . . . , (K ₁ +K₂)+K ₃. . .d _(j) =c _(N,(j−(K1+K2+ . . . +KN−1))) j=(K ₁ +K ₂ + . . . +K_(N−1))+1, (K ₁ +K ₂ + . . . +K _(N−1))+2, . . . , (K ₁ +K ₂ + . . . +K_(N−1))+K _(N)

The multiplexer 200 is included in a transmitting device and itscounterpart is a demultiplexer in a receiving device. The demultiplexerreversely performs the operation of the multiplexer 200, that is,segments an input frame into N blocks and feeds the N blocks tocorresponding radio frame dematchers.

FIG. 7 is a flowchart illustrating a radio frame multiplexing procedurein the multiplexer 200. Prior to description of the procedure shown inFIG. 7, terms as used below are defined.

N: total number of radio frame matchers;

i: radio frame matcher index (1, 2, . . . , N); and

RFi: a 10 msec radio frame in an i^(th) radio frame matcher.

The multiplexer 200 sets the radio frame matcher index i to an initialvalue 1 in step 711 and stores a radio frame received from the i^(th)radio frame matcher in a multiplexing buffer in step 713. In step 715,the multiplexer 200 increases the radio frame matcher index i by 1.Then, the multiplexer 200 checks whether the increased index i isgreater than the total number N of radio frame matchers in step 717. Ifi is equal to or smaller than N, the multiplexer 200 returns to step713. If i is greater than N, the multiplexer 200 ends the multiplexingprocedure. As described above, the multiplexer 200 sequentially storesradio frames received from the radio frame matchers in the multiplexingbuffer and generates a multiplexed frame of size P that is a serial dataframe.

Physical Channel Segmentation

The physical channel frame segmenter 300 operates in the same manner forthe uplink and the downlink.

Let the bits of a serial data frame output from the multiplexer be d₁,d₂, . . . , d_(p), and the number of physical channels be M. Then,

-   output bits of the physical channel frame segmenter for physical    channel #1:    e _(1,j) =d _(j) j=1,2, . . . , P/M-   output bits of the physical channel frame segmenter for physical    channel #2:    e _(2,j) =d _((j+P/M)) j=1,2, . . . , P/M-   output bits of the physical channel frame segmenter for physical    channel #M:    e _(M,j) =d _((j+(M−1)P/M)) j=1,2, . . . , P/M

The above physical channel segmentation scheme in the physical channelsegmenter is advantageous in that the best use of the effects of thesecond interleavers are made. Therefore, the probability of bit errorsafter decoding at a receiver, caused by burst error on a fading channel,can be minimized. For a data rate of ⅓ for a general channel coder,three symbols represent one information bit. Another physical channelsegmentation scheme with M=3 and P=30 can be further contemplated asshown below:

-   Bits before physical channel segmentation:

0 1 2 3 4 5 6 7 8 9 10 . . . 29

-   Bits after physical channel segmentation:

Physical channel #1: 0 3 6 9 12 . . . 27

Physical channel #2: 1 4 7 10 13 . . . 28

Physical channel #3: 2 5 8 11 14 . . . 29

Since the same second interleaver is used in this three-physical channelsegmentation, three input symbols are always consecutive after secondinterleaving. Accordingly, the three consecutive symbols are highlylikely to experience errors at fading at a specific time point.

Meanwhile, a segment having consecutive bits of the same number isassigned to one physical channel in the present invention and thus

-   Bits before physical channel segmentation:

0 1 2 3 4 5 6 7 8 9 10 . . . 29

-   Bits after physical channel segmentation:

Physical channel #1: 0 1 2 3 . . . 9

Physical channel #2: 10 11 12 13 . . . 29

Physical channel #3: 20 21 22 23 . . . 29

After second interleaving, three physical channels have different timein the same bit position, thereby decreasing the probability ofconcurrent errors in three symbols representative of one information bitdue to fading. Therefore, a receiver may have a lower bit error rate(BER) in the present invention than the above-described physical channelsegmentation.

The physical channel frame segmenter is included in a transmittingdevice and its counterpart is a physical channel desegmenter in areceiving device. The physical channel desegmenter performs the reverseoperation of the physical channel segmenter, that is, sequentiallyarranges M physical channel frames and assembles them into one frame.

FIG. 8 is a flowchart illustrating a physical channel frame generatingprocedure in the physical channel segmenter. Terms as used below willfirst be defined.

m: physical channel index (1, 2, . . . , M);

M: total number of physical channels; and

P: index data block size in bits.

Referring to FIG. 8, the physical channel segmenter 300 sets thephysical channel index m to an initial value 1 in step 811 and reads adata block of size P/M from input data of size P and stores it in anm^(th) physical channel buffer in step 813. Then, the physical channelsegmenter 300 increases the physical channel index m by 1 in step 815and checks whether the increased physical channel index m is greaterthan the total number M of the physical channels in step 817. If m isequal to or smaller than M, the physical channel segmenter 300 returnsto step 813. On the contrary, if m is greater than M, the physicalchannel segmentation ends.

Implementation of Receiving device

FIG. 4 is a block diagram of a channel receiving device having thecounterparts of the radio frame segmenter, the multiplexer, and thephysical channel segmenter as described above.

Referring to FIG. 4, a physical channel memory 411 storessecond-interleaved symbols. A first address generator 412 generates awrite address for every M bits of the second-interleaved symbols atwhich the M bits will be stored in the physical channel memory 411. Asecond address generator 413 generates a read address for sequentiallyreading the symbols from the physical channel memory 411 when thesymbols are completely stored in the physical channel memory 411. Ademultiplexer 414 distributes symbols received from the physical channelmemory 411 to N buffers 415 to 4N5. The buffers 415 to 4N5 feed thestored symbols to corresponding radio desegmenters 417 to 4N7 withoutrate dematching if the symbols are for the downlink and to ratedematchers 416 to 4N6 if the symbols are for the uplink. The ratedematchers 416 to 4N6 perform zero symbol insertion and symbolcombination, in the reverse order of rate matching. The radio framedesegmenters 417 to 4N7 assemble the symbols received from the ratedematchers 416 to 4N6 to data of corresponding transport channel TTIsand transmit the desegmented data to a channel decoder for channeldecoding.

For a write operation, the first address generator 412 operates to writeevery M bits in the physical channel memory 411, that is a buffer memoryfor storing symbols received after second deinterleaving. Therefore, thephysical channel memory 411 receives a total of P symbols from thesecond interleaver by operating P/M times. When there is no data on eachchannel coding & multiplexing channel, the total number of receivedsymbols is smaller than P. Hence, a maximum buffer size is P. Uponcompletion of the write operation, the second address generator 413generates read addresses and symbols are read from the physical channelmemory 411 in the address generation order. The read operation isperformed in (L_(i)+r_(i))/T_(i)(=R_(i)) units. By reading N frames ofsize R_(i), a total of P symbols are transmitted to the N buffers 415 to4N5 through the demultiplexer 414. Each buffer has a size of T_(i)×R_(i)(i=1, 2, 3, . . . , N). In this course, the demultiplexer 414 serves todistinguish N symbols. The classified symbols are transmitted directlyto the radio frame desegmenters 417 to 4N7 without rate dematching ifthey are the downlink ones, whereas the symbols are subjected to ratedematching if they are the uplink ones. That is, the rate dematchers 416to 4N6 implements zero symbol insertion and symbol combination, which isthe reverse operation of rate matching. Then, the radio framedesegmenters 417 to 4N7 transmit desegmented symbols to correspondingchannel decoders for channel decoding. As noted from the abovedescription, the operation of the receiving device is basically thereverse of that of the transmitting device.

In accordance with the present invention as described above, radio framesegmentation, multiplexing, and physical channel segmentation formultiplexing & channel coding are defined in detail. Frames of varioustypes generated from channel coders are converted to radio frames,multiplexed, and converted to physical frames. The physical frames arethen assigned to physical channels. Therefore, uplink and downlinktransmitting devices in a CDMA communication system can implementvarious communication services such as transmission of voice, data, andimages.

While the invention has been shown and described with reference tocertain preferred embodiments thereof, it will be understood by thoseskilled in the art that various changes in form and details may be madetherein without departing from the spirit and scope of the invention asdefined by the appended claims.

1. A method of generating a composite transport channel in a systemhaving at least two transport channels, comprising the steps of:receiving at a multiplexer a radio frame from each transport channel;and multiplexing the radio frames into a composite transport channel,wherein if the bits subject to the multiplexing are defined as c_(N,1),c_(N,2), . . . , c_(N,KN), where N is a channel number and KN representsthe number of bits in a radio frame, and if the result of themultiplexing is d₁, d₂, . . . , d_(p), where p is the number of bits,then, when j=1, 2, 3, . . . , P (P=K₁+K₂+ . . . +K_(N)), themultiplexing is defined byd _(j) =c _(i,j) for j=1, 2, . . . , K ₁,d _(j) =c _(2,(j−K1)) for j=K ₁+1, K ₁+2, . . . , K ₁ +K ₂,d _(j) =c _(3,(j−(K1+K2))) for j=(K ₁ +K ₂)+1, (K ₁ +K ₂)+2, . . . , (K₁ +K ₂)+K ₃. . .d _(j) =c _(N,(j−(K1+K2+ . . . +KN−1))) for j=(K ₁ +K ₂ + . . . +K_(N−1))+1, (K ₁ +K ₂ + . . . +K _(N−1))+2, . . . , (K ₁ +K ₂ + . . . +K_(N−1))+K _(N).
 2. A channel coding and multiplexing apparatus for aCode Division Multiple Access (CDMA) communication system, in which dataframes are received via a plurality of transport channels and convertedto data frames of multi-code physical channels, the apparatuscomprising: a number of radio frame matchers, each radio frame matcherincluding an interleaver that interleaves data in a data frame and aradio frame segmenter that segments the interleaved data frame into oneor more radio frames; a multiplexer that multiplexes the radio framesfrom the number of radio frame matchers into a serial data frame; and aphysical channel segmenter that segments the serial data frame by anumber of physical channels and outputs one or more segmented physicalchannel frames to corresponding physical channels, wherein the segmentedphysical channel frames for a physical channel #1 are output ase_(1j)=d_(j), the segmented physical channel frames for a physicalchannel #2 are output as e_(2j)=d_((j+P/M)) and the segmented physicalchannel frames for a physical channel #M are output ase_(Mj)=d_((j+(M−1)P/M)), and wherein bits of the serial data frameoutput from the multiplexer are d₁, d₂, . . . . , d_(p), the number ofphysical channels is M, a size of the serial data frame output from themultiplexer is P, and j =1, 2, . . . , P/M.
 3. A channel coding andmultiplexing method for a Code Division Multiple Access (CDMA)communication system, in which data frames are received via a pluralityof transport channels and converted to data frames of multi-codephysical channels, the method comprising: interleaving data in a dataframe; segmenting the interleaved data frame into one or more radioframes in a number of radio frame matchers; multiplexing the radioframes from the number of radio frame matchers into a serial data frame;and segmenting the serial data frame by a number of physical channelsand outputting segmented physical channel frames to correspondingphysical channels, wherein the segmented physical channel frames forphysical channel #1 are output as e_(1j)=d_(j), the segmented physicalchannel frames for physical channel #2 are output as e_(2j)=d_((j+P/M)),and the segmented physical channel frames for physical channel #M areoutput as e_(Mj)=d_((j+(M−1)p/M)), and wherein bits of the serial dataframe output from the multiplexer are d₁, d₂, . . . , d_(p), the numberof physical channels is M, a size of the serial data frame output fromthe multiplexing step is P, and j=1,2, . . . , P/M.
 4. A channel codingand multiplexing apparatus for a Code Division Multiple Access (CDMA)communication system, in which data frames are received via a pluralityof transport channels and multiplexed to a serial data frame, theapparatus comprising: a number of radio frame matchers, each of theradio frame matchers determining a number of filler bits and insertingthe determined number of filler bits into a data frame at apredetermined position, and each of the radio frame matchers including aradio frame segmenter that segments the data frame having the insertednumber of filler bits into one or more radio frames; and a multiplexerfor multiplexing the radio frames from the number of radio framematchers into the serial data frame.
 5. The channel coding andmultiplexing apparatus of claim 4, wherein each filler bit position is alast bit position of a corresponding radio frame.
 6. The channel codingand multiplexing apparatus of claim 5, wherein at least one radio framewith a filler bit is a last radio frame.
 7. The channel coding andmultiplexing apparatus of claim 4, further comprising a physical channelsegmenter for segmenting the multiplexed serial data frame by the numberof the physical channels and outputting segmented physical channelframes to corresponding physical channels.
 8. A channel coding andmultiplexing method for a Code Division Multiple Access (CDMA)communication system in which data frames are received via a pluralityof transport channels and multiplexed into a serial data frame, themethod comprising: receiving data frames; determining a number of fillerbits; inserting the determined number of filler bits into a data frameat a predetermined position; segmenting the data frame including thefiller bits into one or more radio frames in a number of radio framematchers; and multiplexing the radio frames from the number of radioframe matchers into the serial data frame.
 9. The channel coding andmultiplexing method of claim 8, wherein each filler bit position is alast bit position of a corresponding radio frame.
 10. The channel codingand multiplexing method of claim 9, wherein at least one radio framewith a filler bit is a last radio frame.
 11. The channel coding andmultiplexing method of claim 8, further comprising segmenting themultiplexed serial data frame by the number of the physical channels andoutputting segmented physical channel frames to corresponding physicalchannels.
 12. A channel coding and multiplexing apparatus for a CodeDivision Multiple Access (CDMA) communication system, in which dataframes are received via a plurality of transport channels andmultiplexed into a serial data frame, the apparatus comprising: aplurality of radio frame matchers, each of the radio frame matchersdetermining a number of filler bits and inserting the determined numberof filler bits into a data frame at a predetermined position, whereineach of the radio frame matchers includes a radio frame segmenter forsegmenting the data frame having the inserted number of filler bits intoone or more radio frames; and a multiplexer for multiplexing the radioframes from the number of radio frame matchers into the serial dataframe.
 13. The channel coding and multiplexing apparatus of claim 12,wherein each filler bit position is a last bit position of acorresponding radio frame.
 14. The channel coding and multiplexingapparatus of claim 13, wherein at least one radio frame with a fillerbit is a last radio frame.
 15. The channel coding and multiplexingapparatus of claim 12, further comprising a physical channel segmenterfor segmenting the multiplexed serial data frame by the number of thephysical channels and outputting segmented physical channel frames tocorresponding physical channels.